Two point charges of 2 C each are separated from each other by a distance of 1 m in water (\( K = 80 \)). The force between the charges is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 4.5\times10^{8}\,\mathrm{N} \)
In a medium of dielectric constant \( K \) the force given by Coulomb's law is reduced by the factor \( K \).
\( \displaystyle F = \frac{1}{4\pi\varepsilon_0 K}\,\frac{q_1 q_2}{r^{2}} = \frac{9\times10^{9} \times 2 \times 2}{80 \times 1^{2}} \)
\( \displaystyle F = \frac{3.6\times10^{10}}{80} = 4.5\times10^{8}\,\mathrm{N} \)